Radiotherapy uses a beam of ionizing radiation to destroy malignant cells as part of cancer treatment. Particle therapy is a form of radiotherapy that utilizes a beam of protons, neutrons or atomic nuclei. The most common type of particle therapy is proton therapy.
Conventional systems for characterizing radiotherapy beams facilitate the measurement of the beam's properties in order to assure its suitability for its intended purpose. Based on the measurements that are made the system administrator can adjust a beam's characteristics such as its location, field size and the depth at which its energy is deposited.
Conventional systems for characterizing beams use scintillation screens, mirrors, CCD cameras, ion chambers, ion chamber arrays with and without buildup, film, and wire chambers. Such systems suffer from significant drawbacks. For example, beam characterization systems that use scintillation screens and mirrors may use indirect conversion methods. Charge-coupled device (CCD) cameras can be burdened by a reliance on multiple conversions (proton-light-mirror-charge) and can cause geometric distortion due to their mechanical construction. Moreover, the size of the CCD sensor can be large and can make handling difficult. Beam characterization systems that use ion chambers and ion chamber arrays can provide only limited measurement resolutions meaning that the beam cannot be precisely characterized. Beam characterization systems that use wire chambers or film cannot provide real-time measurements because, for example, time is needed to develop the film.
In summary, there is a continuing need to improve the speed and resolution of beam characterization systems.